Interaction of catecholamine precursor l-Dopa with lysozyme: A biophysical insight

Area of Science:

• Biophysics
• Biochemistry
• Pharmacology

Background:

• Lysozymes are crucial enzymes involved in various biological processes.
• Understanding protein-ligand interactions is vital for drug development.

Purpose of the Study:

• To investigate the biophysical interactions between L-3,4-dihydroxyphenylalanine (l-Dopa) and human lysozyme (HL) as well as hen egg white lysozyme (HEWL).
• To elucidate the binding mechanisms and thermodynamic parameters governing l-Dopa-lysozyme interactions.
• To explore the potential implications for drug pharmacodynamics and pharmacokinetics.

Main Methods:

• Spectroscopic techniques (spectrofluorimetry, circular dichroism) were employed to analyze binding.
• Dynamic Light Scattering (DLS) was used to assess changes in protein size.
• Molecular docking simulations were performed to predict binding modes and interactions.

Main Results:

• l-Dopa exhibited significant binding to both HL and HEWL, with a binding constant (Kb) of approximately 10^4 M^-1.
• Spectrofluorimetric analysis showed fluorescence quenching, indicating l-Dopa interaction.
• Far-UV CD spectra revealed an increase in helical content, and DLS showed a decrease in hydrodynamic radii upon l-Dopa binding.
• Molecular docking confirmed hydrogen bonding and hydrophobic interactions between l-Dopa and lysozymes.

Conclusions:

• l-Dopa spontaneously interacts with HL and HEWL, leading to conformational changes.
• The binding is characterized by hydrogen bonding and hydrophobic interactions.
• This research provides insights into the molecular interactions of l-Dopa with lysozymes, relevant for pharmaceutical applications.